Design and characterization of metasurfaces for LIDAR applications

Metasurfaces is an emerging technology, poised to disrupt diverse application sectors of the optical industry, including AR/VR, Light imaging and Ranging (LiDAR) and optical design. With respect to conventional diffractive optical elements (DOE), Metasurfaces provide considerably higher scalability, larger field of view (FoV) and enhanced diffraction efficiencies (DE). In addition, their design flexibility allows for arbitrary intensity, phase and polarization far-field distribution. Most of the commercial imaging LiDAR devices rely on light scanning architectures that enforce compromising between FoV and frame rate. Splitting incident power to project a point-cloud of intensity distribution in the far-field, flash LiDAR systems can improve imaging speed, but at the expense of the imaging depth. To overcome these limitations, metasurfaces have been proposed as a good alternative to conventional LiDAR components, for both detection and illumination. However, further efforts in improving design, fabrication and characterization of those functionalized surfaces are still needed. Here, we demonstrate the advantage of design flow based on inverse design capability for the generation of a metasurface targeting advanced beam steering and arbitrary point-cloud illumination for 3D sensing. The development of metasurface-based projectors, able to generate arbitrary light distributions -beyond classical diffraction patterns- would open new LiDAR imaging capabilities with improved resolution and performances.